Black Pigment Composition For Heat-Shielding Coating, Use Of Same, Heat-Shielding Coating Using Same And Use Of Same For Shading And Coating

Abstract

Provided are a black pigment composition for heat-shielding coatings that has superior infrared radiation transmittance, approximates the hue of chromium-based black coatings not only in a dark color, but also in a light color as well and therefore facilitates hue adjustment when mixed with a chromatic coating, has superior weather resistance and is also advantageous in terms of cost, as well as a heat-shielding coating that uses the same, and a shading method. The black pigment composition for heat-shielding coatings contains, at least, a phthalocyanine blue pigment as a first pigment and a phthalocyanine green pigment as a second pigment, and further contains at least one other chromatic pigment, wherein, regarding the amounts in parts by weight of the phthalocyanine blue pigment as Mb, of the phthalocyanine green pigment as Mg, and of the total of the at least one other chromatic pigment as Mn,1.5<Mg / Mb<4.0, and2<Mb<2017<Mg<4045<Mn<63,are established.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a black pigment composition for heat-shielding coatings.[0003]2. Description of the Related Art[0004]During the summer, heat generated by sunlight radiated onto the roofs and outer walls of buildings and paved streets accumulates. Due to this, cooling load increases during the day and the heat is released during the night, which causes a phenomenon known as the heat island phenomenon, in which ambient temperature does not fall even after sundown in urban areas, and is becoming a serious problem.[0005]One example of a method used to relieve this heat island phenomenon consists in applying, to building roofs, outer walls and the like, a coating to which infrared reflection and thus, heat shielding properties are imparted, thereby not allowing sunlight energy to accumulate inside the buildings by causing it to be reflected from the roofs and outer walls thereof, and development of such a me...

AI Technical Summary

Benefits of technology

[0018]An object of the present invention is to provide a black pigment composition for heat-shielding coatings that has superior infrared radiation transmittance, approximates the hue of chromium-based black heat-shielding coatings not only in a dark color, but also in a light color as well, thereby facilitating hue adjustment when mixed with a chromatic coating, has superior weather resistance and is also advantageous in terms of cost, as well as a heat-shielding coating that uses the same, and the use thereof for shading and coating.

[0027]According to the present invention, a black pigment composition for heat-shielding coatings can be obtained, which shows solar heat shielding effects, has superior weather resistance, is able to be used as an alternative to chromium-based pigments conventionally used as pigments for heat-shielding coatings because it approximates the hue of chromium-based black pigments under both highly-dark colored black color and light-colored conditions, facilitates shading of coatings to an intermediate color and the like, and is advantageous in terms of cost.

Problems solved by technology

Due to this, cooling load increases during the day and the heat is released during the night, which causes a phenomenon known as the heat island phenomenon, in which ambient temperature does not fall even after sundown in urban areas, and is becoming a serious problem.

One example of a method used to relieve this heat island phenomenon consists in applying, to building roofs, outer walls and the like, a coating to which infrared reflection and thus, heat shielding properties are imparted, thereby not allowing sunlight energy to accumulate inside the buildings by causing it to be reflected from the roofs and outer walls thereof, and development of such a method is currently actively proceeding at many companies.

However, when a white coating is applied to building outer walls, warehouse roofs and the like, it is extremely glaring due to its high reflectance, and this may make it unpleasant for nearby residents and result in troubles.

Although a method consisting in lowering brightness by adding carbon black to the coatings has been considered as means for reducing such glaringness, a further problem occurs in that heat-shielding effects decrease due to absorption of radiation in the infrared wavelength region by the carbon black pigment.

Namely, in the case where the hue of a coating color that uses an alternative pigment to a conventional chromium-based pigment differs from that of the latter, the method and procedure used for shading also differ, and as a result thereof, it becomes necessary to carry out bothersome work when applying the coating on site.

In addition, there is also increased likelihood of the occurrence of troubles caused by the hue of a coated article differing from the hue specified by a customer.

However, such pigments which are chromium-free and imparted with said properties frequently use rare metals in the place of chromium, thereby making them extremely expensive and unsuitable for use as an alternative pigment.

However, optimum conditions for obtaining a pigment composition able to approximate the hue of a light-colored chromium-based black coating, as described in 2), above have not been found.

However, for reasons such as weather resistance, price or others, a coating that satisfies such a level of required performance has not yet been realized with a chromium pigment alternative.